Antisense Monocyte Chemoattractant Protein-1 Gene Inhibits Experimental Vein Graft Intimal Hyperplasia

Background: The development of intimal hyperplasia is a major cause of vein graft failure. Monocyte chemotactic protein 1 (MCP-1) is the specific monocyte chemoattractant which plays an important role for the recruitment of monocytes in vessel. The main pathological features of vein graft intimal hyperplasia are characterized by continuous overexpression of MCP-1, monocytes/macrophages infiltration throughout the layers, following proliferation of smooth muscle cells, extracellular matrix deposition, and neointima formation. Using antibody (anti-MCP-1 antibody or anti-monocyte/macrophage antibody), corticoid and immunosuppressor can slowdown the pathology process, reduce intimal hyperplasia. In our study, the effects of in vivo local expression of recombinant antisense MCP-1 gene in a rabbit jugular vein-to-artery model were examined in an effort to clarify the role of MCP-1 and monocytes in the development of neointima formation. Meanwhile, evaluated the possibility of nanoparticle as a new vector in specific gene transference. Method: An eukaryotic expression plasmid of antisense MCP-1 gene was constructed by inserting rabbit MCP-1 cDNA into LNCX vector in a reversed orientation. Recombinant gene was transfected into cultured aortic smooth muscle cells of rabbit by cationic lipids (lipofectamine) and nanoparticle respectively in vitro. The integration and expression of recombinant gene was measured with PCR or Northern hybridization correspondingly. For in vivo study, jugular vein-to-artery bypass grafting procedures were performed on 20 New Zealand White rabbits, of which 4 grafts were transferred with LNCX vectors, 6 grafts with antisense MCP-1 (200μg) by cationic liposome (DOTAP), 6 grafts with antisense MCP-1 (200μg) by nanopaticle and 4 grafts as control. Fourteen days after surgery grafts were harvested. The expression of antisense MCP-1 and its effect on MCP-1 in vein grafts were detected by dot blot. Grafts were processed for morphologic evaluation and immunohistochemistry analysis.